In a distributed application network with a plurality of data servers of different platforms a plurality of client applications must be enabled to access business data which are stored on said servers. When there are only relational data bases in the system such an access can be easily realized by prior art standard interfaces between client application and relational data base which is hosted on for example a centralized located data base server. By help of standard interfaces like JDBC/ODBC or CLI any relational database can be explored. Said access is implemented using e.g. the DRDA standard, i.e. distributed relational data base architecture for IBM DB2 relational database architecture. Standard transfer protocols like APPC or TCP/IP are used for transferring the data across the network.
The access is complicated, however, when in the same distributed data base application network there are some data resources which must be accessed as well but which are not stored in a relational data base but, for example, stored in a hierarchical data base or in sequential files as it is the case for example in files which are accessed by VSAM (virtual storage access method) or for data which are stored in a hierarchical data base like DL/1. Such data types are further referred to herein as proprietary data types.
Such a system configuration is depicted in FIG. 1 in an exemplary form where a central data base server 10 having the operating system VSE/ESA hosts a relational DB/2 data base 12. When one of a plurality of client systems 13—a computer system with any operating system onto which is implemented some business application 14—wants to access the data stored in the relational data base 12 via the network it uses the standard interfaces JDBC, or ODBC, or CLI depending of the platform operating system in use.
The universal standard connecting interface to the relational data base is depicted with the bi-directional arrow 18. Any request for accessing the relational data can be satisfied easily. If, however the same client application wants to access data stored in a VSAM-file 20 or data which are stored in a hierarchical data base 22 the access must be realized by using proprietary vendor interfaces 24, and 26 respectively which serve as adapter programs in order to access the non-relational, proprietary data in either of the data storages 20, or 22, respectively.
The disadvantage is that such adapter programs must be programmed and maintained individually for each application product version and must be installed in a plurality of locations in the distributed application system. This additional service is expensive and prone to error.